1. Field of the Invention
The invention relates generally to a machine tool with a working area cover including at least one door for allowing access to a working area of the machine tool.
2. Discussion of the Prior Art
In conventional machine tools having a working area cover, the doors are generally formed as rectilinearly shiftable flat doors. To provide sufficiently large access to the working area of the machine tool, often two diagonally arranged and separately operable sliding doors are provided which laterally protrude over the machine stand by a considerable amount in their opened positions and may cause interference with the operator. In addition, sealing problems occur in the area of the linings of the two sliding doors in their closed positions and special precautions have to be taken to prevent dripping of the cooling agent from the doors which are laterally protruding in the opened position. Furthermore, relatively complicated sliding guides are required for such sliding doors on the bottom edge as well as on the upper edge. One would prefer a machine tool with a working area cover that provides enhanced and simplified access to the working area without interfering protrusions or edges.
According to the present invention, the door of a machine tool of the above mentioned type is a round door turnable about a vertical axis. One advantage of the present invention is that the outer dimensions of the machine tool remain unchanged even with the door fully opened. Further, with the door in the opened state, there are no laterally protruding sections of the door by which access may be hindered and motion about the machine might be limited. With only one round door that can be turned to the side, access to the working area can be provided which would only be obtainable by two diagonally arranged sliding doors in conventional embodiments. In addition, the corner areas in conventional embodiments may be omitted which eliminates a dead space that can not be utilized for machining. This is particularly the case in machine tools provided with turn tables. The working area cover can be optimally located in a potential interference area of a turn table, whereby space economy may be achieved. For example, the round door may be formed in the shape of a cylinder jacket segment having a round outer wall and an upper cover surface. Thus, a very stable and stiff door construction is obtainable, whereby the sealing and guidance are also simplified.
One constructively simple and cost effective guidance of the round door may be constructed by making the round door turnable about an upper turning joint and slidable on a lower round guide. In this way, a complicated sliding guide on the upper side of the door may be omitted.
In an embodiment which simplifies the removal of chips, the lower round guide may, for example, be disposed on a semicircular bottom pan which is either integrally formed with the machine stand or mounted on the stand. The semicircular bottom pan contains no interfering corners or protrusions at which chips may accumulate. The bottom pan has a bottom surface obliquely inclined toward a recess such that the machining chips may be guided toward the recess. In the recess, a conveyor worm, for example, may be formed for removing the chips through a chip removing channel.
For protecting the round guide from contamination by the machining chips during machining, the round door has a lower cover surface extending obliquely inward over the round guide. Thereby the complete curved guide may be covered when the door is closed. Chips or the like produced during the machining process may slide along the oblique end surface and fall into the bottom pan from where they may be removed by the conveyor worm.
Observation windows may be formed in the round door for visually monitoring the machining process. Since the observation windows are often intensively sprayed with cooling agents from the inside during the machining process and visual contact with the tool is thereby obscured, at least one rotating pane for tossing off the coolant-lubricant or the chips may be provided. Thereby, visual contact to the machining process may be ensured in at least one small section of the round door even in case of an intense use of coolant-lubricants. Such a rotating pane may be disposed in the round door, for example, within one observation window, or outside of the observation window at the side wall. The rotating pane may, however, also be provided in another section of the working area cover.